1. Field
The invention is in the field of pads or mats used as training aids, supporting surfaces, and force absorbing devices for various sport activities, particularly gymnastics, such as landing and tumbling mats, and high jumping and pole vaulting, such as landing pads in landing pits
2. State of the Art
Many years ago I experimented with a combination constant flow inflatable mat with a top section comprising a wall that when the mat was fully inflated took a convex form. By connecting bungee cords horizontally between the inside of opposite side walls, making the elastic cords shorter than the normal distance between the walls when the mat was fully inflated, the walls expanded when an athlete landed on the top side of the inflated mat. The additional air pressure created by the impact of the athlete when landing on and compressing the mat caused the side walls to expand outwardly. This expansion was resisted by the elastic cords connected inside the mat. This then allowed for a smooth deceleration over a longer distance for the athlete than would be the deceleration distance provided by merely compressing the air in the mat and allowing the normal restricted escape of the air through the unsealed mat.
The bungee cords in combination with a constant flow air mat worked well for absorbing the impact of a falling body when properly designed and adjusted. A constant flow air mat is a six sided air chamber having inside baffles to maintain a desired configuration. The air chamber is not sealed, and therefore, a constant supply of air into the chamber is necessary to keep the chamber inflated. The chamber is thus filled with air by using a continually running squirrel cage type blower. This blower is generally high volume, low air pressure. It is necessary to balance the constant air flow into the air chamber with the constant loss of air from the chamber in a way that creates a pressure in the air chamber. With a particular capacity blower, a particular air pressure will be established in the air chamber. If the pressure in the chamber is to be changed with the same blower supplying air to the chamber, an opening in the chamber has to be created, enlarged, or closed, to change the air flow out of the chamber and thus balance the air flow into the chamber versus the air flow out of the chamber to create a desired pressure. Sometimes to create the deceleration desired to be provided by the mat, it was necessary to provide flaps the would release under a certain pressure created by the impact of the athlete on the mar to release air from the chamber at a controlled rate greater than the normal rate of loss of air from the chamber. This controlled air flow out of the chamber created a controlled collapse of the mat to provide a desired deceleration and cushioning by the mat. With the constant air flow mat, it is very difficult to adjust or change the air pressure in the mat and the energy absorption or energy rebound obtained with the mat. Thus, such mat and blower combination has to be designed for a particular deceleration application, such as a high jump landing pit, or for a rebound application such as a jumping mat for a particular weight range of user. An additional problem with a constant flow air mat is the requirement of having a noisy motor and blower constantly running. Further, it is necessary to have an electrical outlet available and an electrical cord running from the outlet to the blower motor.
In recent years, long constant flow air mats, fifteen to sixty feet long and six to seven feet wide, have been used as tumbling mats. These mats require a strong and generally loud blower to keep the mats firm enough to afford some rebound to the athlete tumbling onto or on the mat. Further, these constant flow mats have required a strong nylon mesh vinyl coated fabric, so there is very little natural rebound or stretch and response properties in this fabric. I have attempted to make an airtight inflatable mat that forms a sealed air chamber that can be inflated and does not require constant air flow from a blower. These mats, however, when made of a strong supported vinyl fabric, have been found too hard and unpleasant to tumble on. To try to solve this problem, I have attempted to make airtight inflatable mats using unsupported vinyl fabric which has a natural resiliency or rebound. I have made a number of products directed to gymnastic training using sealed air chambers and heavy-duty unsupported vinyl fabric. These are described in my copending patent application Ser. No. 11/156,065, hereby incorporated by reference. While these products have proven of great benefit to the gymnastics world, they have generally been best suited to the beginner and intermediate level gymnast where the gymnast applies less force to the mats than do an advanced gymnast. This is because the seams and baffle attachments in many of these mats come apart when subjected to extreme sudden applied forces, such as those applied routinely by advanced gymnasts landing on and rebounding from these mats. Further, while these mats provide good rebound for normal gymnastics maneuvers, they do not provide the larger deceleration distances needed for deceleration of a high jump or pole vault athlete or in other situation where cushioning a fall is the purpose of the pad or mat.